System and methods for reducing ghosting

Abstract

The presently disclosed embodiments are directed to imaging members useful in electrostatography. More particularly, the embodiments pertain to an improved development systems for electrophotographic imaging and printing apparatuses and machines in which ghosting print defects are reduced, and more particularly, is directed to a method for reducing positive ghosting in such systems.

1. A method for developing a latent image on an imaging surface, comprising:
 charging an imaging surface, further comprising
 charging the imaging surface to a high voltage to accelerate removal of hole electron pairs, wherein the imaging surface is charged to the high voltage for a first portion of rotation, the first portion of rotation being about 60 degrees of rotation, 
 reducing surface voltage of the imaging surface to a low voltage to neutralize surface charge of the imaging surface, and 
 charging the imaging surface to a target voltage to produce uniformity of the surface charge; 
 
 exposing the imaging surface to an image to form an electrostatic latent image; 
 forming a toner image with a toner-containing developer by developing the electrostatic latent image on the imaging surface; and 
 transferring the toner image to a transfer substrate, wherein obtaining uniform surface charge on the imaging surface substantially reduces ghosting print defect. 
 
   
   
     2. The method of  claim 1 , wherein charging the imaging surface to the high voltage for the first portion of rotation is performed by a first scorotron or a first corotron. 
   
   
     3. The method of  claim 1 , wherein the imaging surface is reduced to the low voltage for a second portion of rotation, the second portion of rotation being about 10 degrees of rotation. 
   
   
     4. The method of  claim 3 , wherein charging the imaging surface to the low voltage for the second portion of rotation is performed by a second scorotron or a second corotron. 
   
   
     5. The method of  claim 4 , wherein the second scorotron is selected from the group consisting of an AC scorotron and a negative DC scorotron, and the second corotron is selected from the group consisting of an AC corotron and a negative DC corotron. 
   
   
     6. The method of  claim 1 , wherein the imaging surface is charged to the target voltage for a third portion of rotation, the third portion of rotation being about 20 degrees of rotation. 
   
   
     7. The method of  claim 6 , wherein charging the imaging surface to the target voltage for the third portion of rotation is performed by a third scorotron or a third corotron. 
   
   
     8. The method of  claim 1  further including cleaning residual toner from the imaging surface. 
   
   
     9. The method of  claim 1 , wherein the high voltage to accelerate removal of hole electron pairs is over 1000 volts. 
   
   
     10. The method of  claim 1 , wherein the low voltage to neutralize surface charge of the imaging surface is below 600 volts. 
   
   
     11. The method of  claim 1 , wherein the target voltage is about 600 volts. 
   
   
     12. The method of  claim 1 , wherein the ghosting print defect is positive ghosting. 
   
   
     13. The method of  claim 1 , wherein the imaging surface comprises amorphous silicon. 
   
   
     14. A method for developing a latent image on an imaging surface, comprising:
 charging an imaging surface, further comprising
 charging the imaging surface to about 1000 volts or more for a first portion of rotation to accelerate removal of hole electron pairs, 
 reducing surface voltage of the imaging surface to from about 500 volts to about 550 volts for a second portion of rotation to neutralize surface charge of the imaging surface, and 
 charging the imaging surface to about 600 volts for a third portion of rotation to produce uniformity of the surface charge; 
 
 exposing the imaging surface to an image to form an electrostatic latent image; 
 forming a toner image with a toner-containing developer by developing the electrostatic latent image on the imaging surface; and 
 transferring the toner image to a transfer substrate, wherein obtaining uniform surface charge on the imaging surface substantially reduces ghosting print defect. 
 
   
   
     15. A system for developing a latent image on an imaging surface, comprising:
 a charging unit for charging an imaging surface, the charging unit comprising
 a first scorotron or first corotron for charging the imaging surface to a high voltage for a first portion of rotation to accelerate removal of hole electron pairs, 
 a second scorotron or a second corotron for reducing surface voltage of the imaging surface to a low voltage for a second portion of rotation to neutralize surface charge of the imaging surface, and 
 a third scorotron or third corotron for charging the imaging surface to a target voltage for a third portion of rotation to produce uniformity of the surface charge; 
 
 an exposing unit for exposing the imaging surface to an image to form an electrostatic latent image; 
 a toner-containing developer for forming a toner image by developing the electrostatic latent image on the imaging surface; and 
 a transferring unit for transferring the toner image to a transfer substrate, wherein obtaining uniform surface charge on the imaging surface substantially reduces ghosting print defect. 
 
   
   
     16. The system of  claim 15 , wherein the high voltage to accelerate removal of hole electron pairs is over 1000 volts and the low voltage to neutralize surface charge of the imaging surface is below 600 volts. 
   
   
     17. The system of  claim 15  further including a cleaner for cleaning residual toner from the imaging surface. 
   
   
     18. The system of  claim 15 , wherein the exposing unit comprises a LED light bar. 
   
   
     19. The system of  claim 16 , wherein the second scorotron is selected from the group consisting of an AC scorotron and a negative DC scorotron, and the second corotron is selected from the group consisting of an AC corotron and a negative DC corotron.